How to Stain and Seal a Concrete Floor

If you want a beautiful and trendy coffeehouse look in your kitchen, living room, or even a bedroom, staining your concrete floor is a bold way to achieve it. The problem is that it is a specialized process that few people have done themselves, so it's tough to get good advice on how to stain a concrete floor correctly.

If you've seen a stained concrete floor you like, take a picture of it and take it to your local home improvement store or paint store. This will provide a good start. There are different types of staining processes, but this article will cover the acid stain and sealing process.

1. Remove old flooring

The first step is to remove any old carpet or other flooring and make sure you're happy with the shape the concrete is in. Builders often make marks on concrete slabs knowing they will be covered up, and carpet installers often nail down tack strips or glue down padding that can leave permanent marks on the concrete. It is possible to remove most of these markings, but there will likely be imperfections showing through the finished floor. The beauty of stained concrete is that the variegated finish blends well with imperfections, so don't think that just because your floor has issues, you can't stain it.

2. Remove markings and glue

Next, remove markings and glue by scraping or with lacquer thinner or a commercial graffiti remover. This can take time, but is well worth the effort. Keep in mind that any solvent-based products will have to be washed off using a degreasing solution (like TSP) that you can purchase at a home improvement store. Acid stains must be applied to oil- and solvent-free surfaces, or they won't react with the concrete.

3. Fill cracks and pits with concrete patch

Now fill any cracks or pits in the concrete with a quick-setting concrete patch. Level it out with a trowel or putty knife and smooth it with a wet sponge. If necessary, sand the patched area lightly after it sets to remove any residue and blend the patched surface with the surrounding area.

4. Mask walls and degrease floor if necessary

You may want to mask walls from overspray at this point. If you've used any solvent-based cleaning products, wash the surface with a degreasing solution and rinse thoroughly. Use a wet-vac or sponge mop to remove extra water if necessary.

5. Apply your acid stain

You're finally ready for your acid stain treatment. Follow the directions of the manufacturer, but usually this entails pouring the acid into a plastic pressure sprayer. Dampen the concrete floor lightly and start spraying the stain over the concrete, working your way from the far corner of the room to the door so you don't have to step on completed areas. It's okay to let the stain pool into the low spots of the concrete; this will give the finish a beautiful leather-like look.

6. Scrub off dried residue and neutralize with baking soda solution

The acid in the stain will react with the concrete and you should see some bubbling as you apply the stain. You can typically let the stain dry for 8 to 24 hours to let it have the greatest affect, then scrub it off with a solution of baking soda and water to neutralize the acid. Rinse the floor thoroughly, removing the water with a wet-vac or sponge mop as required.

7. Apply concrete floor sealer

You'll notice that the floor looked a lot better wet. Once the floor is complete dry, which may take a day or two with fans on it, you need to apply a sealer to bring back the "wet-look" of the floor. Water based sealer is cheaper and works great if you don't want a high-gloss finish. If you want gloss, pay the extra money for a solvent-based concrete floor sealer. Do not, under any circumstance, apply the water-based sealer first, then change your mind and switch to a solvent-based product. Even if the water-based product is completely dry, the solvent-based sealer won't adhere as well and you'll have problems with it pealing up.

In my opinion, the solvent-based glossy sealer looks dramatically better and is worth the extra money to do it right. The sealer gets applied with a brush around the edges and a roller over the rest of the floor. You may apply a second coat if you wish, then you are finished. You should have a beautiful acid-stained concrete floor!